Bump langchain-tests from 0.3.14 to 0.3.20 in /libs/langchain-mongodb

Bumps [langchain-tests](https://github.com/langchain-ai/langchain) from 0.3.14 to 0.3.20.
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](langchain-ai/langchain@langchain-tests==0.3.14...langchain-tests==0.3.20)

---
updated-dependencies:
- dependency-name: langchain-tests
  dependency-version: 0.3.20
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

libs/langchain-mongodb/pyproject.toml

@@ -39,7 +39,7 @@ dev = [
     "pypdf>=5.0.1",
     "langgraph>=0.2.72",
     "flaky>=3.8.1",
-    "langchain-tests==0.3.14",
+    "langchain-tests==0.3.20",
     "pip>=25.0.1",
     "typing-extensions>=4.12.2",
 ]